Using Limits in Joint Blocks to Constrain Motion

This example uses penalty-based limit forces provided by joint blocks to model three different simple systems:

1. Constrained Pendulum: the revolute joint's lower limit prevents the pendulum from swinging to one side as if colliding with a vertical hard stop. The limit force models an elastic collision with no damping.

2. Constrained Piston: the prismatic joint's lower limit ensures the piston stays above the base of the cylinder. The limit force models an inelastic collision with positive damping.

3. Constrained Ball Joint: the spherical joint's upper and lower limits represent socket walls that keep a shaft confined to an asymmetrical region. Both limit forces model elastic collisions with no damping.